gecko/layout/generic/nsTextFrameUtils.cpp

402 lines
14 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Novell code.
*
* The Initial Developer of the Original Code is Novell Corporation.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* robert@ocallahan.org
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsTextFrameUtils.h"
#include "nsContentUtils.h"
#include "nsIWordBreaker.h"
#include "gfxFont.h"
#include "nsTextTransformer.h"
#include "nsCompressedCharMap.h"
#include "nsUnicharUtils.h"
// XXX TODO implement transform of backslash to yen that nsTextTransform does
// when requested by PresContext->LanguageSpecificTransformType(). Do it with
// a new factory type that just munges the input stream. But first, check
// that we really still need this, it's only enabled via a hidden pref
// which defaults false...
// Replaced by precompiled CCMap (see bug 180266). To update the list
// of characters, see one of files included below. As for the way
// the original list of characters was obtained by Frank Tang, see bug 54467.
// Updated to fix the regression (bug 263411). The list contains
// characters of the following Unicode character classes : Ps, Pi, Po, Pf, Pe.
// (ref.: http://www.w3.org/TR/2004/CR-CSS21-20040225/selector.html#first-letter)
// Note that the file does NOT yet include non-BMP characters because
// there's no point including them without fixing the way we identify
// 'first-letter' currently working only with BMP characters.
#include "punct_marks.ccmap"
DEFINE_CCMAP(gPuncCharsCCMap, const);
#define UNICODE_ZWSP 0x200B
PRBool
nsTextFrameUtils::IsPunctuationMark(PRUnichar aChar)
{
return CCMAP_HAS_CHAR(gPuncCharsCCMap, aChar);
}
static PRBool IsDiscardable(PRUnichar ch, PRUint32* aFlags)
{
// Unlike IS_DISCARDABLE, we don't discard \r. \r will be ignored by gfxTextRun
// and discarding it would force us to copy text in many cases of preformatted
// text containing \r\n.
if (ch == CH_SHY) {
*aFlags |= nsTextFrameUtils::TEXT_HAS_SHY;
return PR_TRUE;
}
if ((ch & 0xFF00) != 0x2000) {
// Not a Bidi control character
return PR_FALSE;
}
return IS_BIDI_CONTROL(ch);
}
static PRBool IsDiscardable(PRUint8 ch, PRUint32* aFlags)
{
if (ch == CH_SHY) {
*aFlags |= nsTextFrameUtils::TEXT_HAS_SHY;
return PR_TRUE;
}
return PR_FALSE;
}
PRUnichar*
nsTextFrameUtils::TransformText(const PRUnichar* aText, PRUint32 aLength,
PRUnichar* aOutput,
PRBool aCompressWhitespace,
PRPackedBool* aIncomingWhitespace,
gfxSkipCharsBuilder* aSkipChars,
PRUint32* aAnalysisFlags)
{
// We're just going to assume this!
PRUint32 flags = TEXT_HAS_NON_ASCII;
PRUnichar* outputStart = aOutput;
if (!aCompressWhitespace) {
// Convert tabs and formfeeds to spaces and skip discardables.
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUnichar ch = *aText++;
if (ch == '\t') {
flags |= TEXT_HAS_TAB|TEXT_WAS_TRANSFORMED;
aSkipChars->KeepChar();
*aOutput++ = ' ';
} else if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
} else {
aSkipChars->KeepChar();
if (ch == CH_NBSP) {
ch = ' ';
flags |= TEXT_WAS_TRANSFORMED;
} else if (IS_SURROGATE(ch)) {
flags |= gfxTextRunFactory::TEXT_HAS_SURROGATES;
}
*aOutput++ = ch;
}
}
*aIncomingWhitespace = PR_FALSE;
} else {
PRBool inWhitespace = *aIncomingWhitespace;
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUnichar ch = *aText++;
PRBool nowInWhitespace;
if (ch == ' ' &&
(i + 1 >= aLength ||
!IsSpaceCombiningSequenceTail(aText, aLength - (i + 1)))) {
nowInWhitespace = PR_TRUE;
} else if (ch == '\n') {
if (i > 0 && IS_CJ_CHAR(aText[-1]) &&
i + 1 < aLength && IS_CJ_CHAR(aText[1])) {
// Discard newlines between CJK chars.
// XXX this really requires more context to get right!
aSkipChars->SkipChar();
continue;
}
nowInWhitespace = PR_TRUE;
} else {
nowInWhitespace = ch == '\t';
}
if (!nowInWhitespace) {
if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
nowInWhitespace = inWhitespace;
} else {
if (ch == CH_NBSP) {
ch = ' ';
flags |= TEXT_WAS_TRANSFORMED;
} else if (IS_SURROGATE(ch)) {
flags |= gfxTextRunFactory::TEXT_HAS_SURROGATES;
}
*aOutput++ = ch;
aSkipChars->KeepChar();
}
} else {
if (inWhitespace) {
aSkipChars->SkipChar();
} else {
if (ch != ' ') {
flags |= TEXT_WAS_TRANSFORMED;
}
*aOutput++ = ' ';
aSkipChars->KeepChar();
}
}
inWhitespace = nowInWhitespace;
}
*aIncomingWhitespace = inWhitespace;
}
if (outputStart + aLength != aOutput) {
flags |= TEXT_WAS_TRANSFORMED;
}
*aAnalysisFlags = flags;
return aOutput;
}
PRUint8*
nsTextFrameUtils::TransformText(const PRUint8* aText, PRUint32 aLength,
PRUint8* aOutput,
PRBool aCompressWhitespace,
PRPackedBool* aIncomingWhitespace,
gfxSkipCharsBuilder* aSkipChars,
PRUint32* aAnalysisFlags)
{
PRUint32 flags = 0;
PRUint8 allBits = 0;
PRUint8* outputStart = aOutput;
if (!aCompressWhitespace) {
// Convert tabs to spaces and skip discardables.
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUint8 ch = *aText++;
allBits |= ch;
if (ch == '\t') {
flags |= TEXT_HAS_TAB|TEXT_WAS_TRANSFORMED;
aSkipChars->KeepChar();
*aOutput++ = ' ';
} else if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
} else {
aSkipChars->KeepChar();
if (ch == CH_NBSP) {
ch = ' ';
flags |= TEXT_WAS_TRANSFORMED;
}
*aOutput++ = ch;
}
}
*aIncomingWhitespace = PR_FALSE;
} else {
PRBool inWhitespace = *aIncomingWhitespace;
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUint8 ch = *aText++;
allBits |= ch;
PRBool nowInWhitespace = ch == ' ' || ch == '\t' || ch == '\n' || ch == '\f';
if (!nowInWhitespace) {
if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
nowInWhitespace = inWhitespace;
} else {
if (ch == CH_NBSP) {
ch = ' ';
flags |= TEXT_WAS_TRANSFORMED;
}
*aOutput++ = ch;
aSkipChars->KeepChar();
}
} else {
if (inWhitespace) {
aSkipChars->SkipChar();
} else {
if (ch != ' ') {
flags |= TEXT_WAS_TRANSFORMED;
}
*aOutput++ = ' ';
aSkipChars->KeepChar();
}
}
inWhitespace = nowInWhitespace;
}
*aIncomingWhitespace = inWhitespace;
}
if (outputStart + aLength != aOutput) {
flags |= TEXT_WAS_TRANSFORMED;
}
if (allBits & 0x80) {
flags |= TEXT_HAS_NON_ASCII;
}
*aAnalysisFlags = flags;
return aOutput;
}
// TODO The wordbreaker needs to be fixed. It's buggy, for example, it doesn't
// handle diacriticals combined with spaces
enum SimpleCharClass {
CLASS_ALNUM,
CLASS_PUNCT,
CLASS_SPACE
};
// This is what nsSampleWordBreaker::GetClass considers whitespace
static PRBool IsWordBreakerWhitespace(const PRUnichar* aChars, PRInt32 aLength)
{
NS_ASSERTION(aLength > 0, "Can't handle empty string");
PRUnichar ch = aChars[0];
if (ch == '\t' || ch == '\n' || ch == '\r')
return PR_TRUE;
if (ch == ' ' &&
!nsTextFrameUtils::IsSpaceCombiningSequenceTail(aChars + 1, aLength - 1))
return PR_TRUE;
return PR_FALSE;
}
// like nsSampleWordBreaker::GetClass
static SimpleCharClass Classify8BitChar(PRUint8 aChar)
{
if (aChar == ' ' || aChar == '\t' || aChar == '\n' || aChar == '\r')
return CLASS_SPACE;
if ((aChar >= 'a' && aChar <= 'z') || (aChar >= 'A' || aChar <= 'Z') ||
(aChar >= '0' && aChar <= '9') || (aChar >= 128))
return CLASS_ALNUM;
return CLASS_PUNCT;
}
PRInt32
nsTextFrameUtils::FindWordBoundary(const nsTextFragment* aText,
gfxTextRun* aTextRun,
gfxSkipCharsIterator* aIterator,
PRInt32 aOffset, PRInt32 aLength,
PRInt32 aPosition, PRInt32 aDirection,
PRBool aBreakBeforePunctuation,
PRBool aBreakAfterPunctuation,
PRBool* aWordIsWhitespace)
{
// A space followed by combining diacritical marks is not whitespace!!
PRInt32 textLength = aText->GetLength();
NS_ASSERTION(aOffset + aLength <= textLength,
"Substring out of bounds");
NS_ASSERTION(aPosition >= aOffset && aPosition < aOffset + aLength,
"Position out of bounds");
*aWordIsWhitespace = aText->Is2b()
? IsWordBreakerWhitespace(aText->Get2b() + aPosition, textLength - aPosition)
: Classify8BitChar(aText->Get1b()[aPosition]) == CLASS_SPACE;
PRInt32 len = 0; // length of current "word", excluding first character at aPosition
if (aText->Is2b()) {
nsIWordBreaker* wordBreaker = nsContentUtils::WordBreaker();
const PRUnichar* text = aText->Get2b();
// XXX the wordbreaker currently isn't cluster-aware. We need to make
// it cluster-aware. In the meantime, just reject any word breaks
// inside clusters.
for (;;) {
if (aDirection > 0) {
// Returns the index of the first character of the next word
PRInt32 nextWordPos = wordBreaker->NextWord(text, textLength, aPosition + len);
if (nextWordPos < 0)
break;
len = nextWordPos - aPosition - 1;
} else {
// Returns the index of the first character of the current word
PRInt32 nextWordPos = wordBreaker->PrevWord(text, textLength, aPosition + len);
if (nextWordPos < 0)
break;
len = aPosition - nextWordPos;
}
if (aTextRun->IsClusterStart(aIterator->ConvertOriginalToSkipped(aPosition + len*aDirection)))
break;
}
} else {
const char* text = aText->Get1b();
SimpleCharClass cl = Classify8BitChar(text[aPosition]);
// There shouldn't be any clusters in 8bit text but we'll cover that
// possibility anyway
PRInt32 nextWordPos;
do {
++len;
nextWordPos = aPosition + aDirection*len;
if (nextWordPos < aOffset || nextWordPos >= aOffset + aLength)
break;
} while (Classify8BitChar(text[nextWordPos]) == cl ||
!aTextRun->IsClusterStart(aIterator->ConvertOriginalToSkipped(nextWordPos)));
}
// Handle punctuation breaks
PRInt32 i;
PRBool punctPrev = IsPunctuationMark(aText->CharAt(aPosition));
for (i = 1; i < len; ++i) {
PRInt32 pos = aPosition + i*aDirection;
// See if there's a punctuation break between i-aDirection and i
PRBool punct = IsPunctuationMark(aText->CharAt(pos));
if (punct != punctPrev &&
aTextRun->IsClusterStart(aIterator->ConvertOriginalToSkipped(pos))) {
PRBool punctIsBefore = aDirection < 0 ? punct : punctPrev;
if (punctIsBefore ? aBreakAfterPunctuation : aBreakBeforePunctuation)
break;
}
punctPrev = punct;
}
PRInt32 pos = aPosition + i*aDirection;
if (pos < aOffset || pos >= aOffset + aLength)
return -1;
return i;
}
PRBool nsSkipCharsRunIterator::NextRun() {
do {
if (mRunLength) {
mIterator.AdvanceOriginal(mRunLength);
NS_ASSERTION(mRunLength > 0, "No characters in run (initial length too large?)");
if (!mSkipped || mLengthIncludesSkipped) {
mRemainingLength -= mRunLength;
}
}
if (!mRemainingLength)
return PR_FALSE;
PRInt32 length;
mSkipped = mIterator.IsOriginalCharSkipped(&length);
mRunLength = PR_MIN(length, mRemainingLength);
} while (!mVisitSkipped && mSkipped);
return PR_TRUE;
}